Improvement in rock-drills



O. H. (HANDLE-1%..

Ro ck Drill.

'No. 201,651 Patented March 26,1878.

- INVENTOR 4/MXWJ4Q/ WITNESS C mm ATTORNEYS.

RS, PHOTO-LITHOGRAPHER, WASHINGTON. D u

UNITED STATES PATENT OFFICE.

CHARLES H. CHANDLER, OF FOXCROFT, MAINE, ASSIGNOR TO HIMSELF AND WILLIAM W. CLARK, OF SAME PLACE.

IMPROVEMENT IN ROCK-DR! LLS.

Specification forming part of Letters Patent No. 201,651, dated March 26, 1878; application filed March 2, 1878.

To all whom it may concern:

Be it known that I, CHARLES H. CHAND- LER, of Foxcroft, in the county of Piscataquis and State of Maine, have invented a new and Improved Rock-Drill, of which the following is a specification:

Figure l is a side elevation of my improved rockdrill, and Fig. 2 is an inverted plan view.

Similar letters of reference indicate corresponding parts.

My invention relates to the class of rockdrills that are reciprocated in the operation of drilling; and it consists of a drill having four wings or blades that radiate from the axis of the drill, three of the blades being sharpened and the fourth being squared or made blunt, the object being to crush the drill-chips, keep the bottom of the hole free from buttons, and to prevent the drill from entering too deeply into soft rock.

Referring to the drawing, A is a drill, which is cruciform in transverse section, having three Wings or blades, 1), that are sharpened on their lower edges, and one wing, c, that is squared and is a very little shorter than the other wings or blades. The squared wing, as it descends upon the drillchips cut from the rock, pulverizes them, so that they are easil washed out of the drill-hole by the water use in drilling, and when the drill is used in soft rock the squared wing prevents the drill from 'enterin g too far into the rock.

This improvement not only facilitates drillin'g, but it also improves the work, as the drill will not run, and a perfectly straight hole will be made, that will be both round and smooth.

Having thus described my invention I claim as new and desire to secure by Letters Patent A rock-drill point having one of its wings squared, as and for the purpose herein shown and described.

CHARLES HOLMES CHANDLER.

Witnesses:

J. B. MAGO,

H. O. PRENTIss. 

